<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>添加content内容</title>
<style type="text/css">
#nav {
	margin:20px auto;
	width:200px;
	border:1px solid #f90;
	padding:20px;
	line-height:22px;
	font-size:18px;
}
#nav a {
	display:block;
	font-size:12px;
	line-height:22px;
	color:#00F;
}
/* 筛选链接地址，添加不同的内容 */
a[href$=html]:before {
 content:"网页：";
}
a[href$=jpg]:before {
 content:"图片：";
}
a[href$=doc]:before {
 content:"Word文档：";
}
a[href$=pdf]:before {
 content:url("images/pdf.gif");
}
</style>
</head>
<body>
<div id="nav"><a href="Code4-17.html">登录页面</a> <a href="images/IL5.jpg">杭州风光</a> <a href="images/test.doc">参考资料</a> <a href="images/Pattern.pdf">设计模式培训</a> </div>
</body>
</html>
